Fogging by the condensation of water vapor on goggles has resulted in serious accidents and more generally has been an inconvenience to skiers, motorcyclists and other users.
One solution to this problem has been provided by goggles as disclosed in U.S. Pat. Nos. 4,414,693; 3,591,864; 3,505,680; 3,488,215; 2,665,686 and 1,562,350.
Attempts at fogging prevention have included chemical treatment, double lenses, forced air and electrically heated lenses.
In U.S. Pat. No. 4,414,693, there is disclosed an optical device wherein fogging is prevented by means of transparent hydrophylic polymer integrated with the transmissive surface thereof.
The safety goggle claimed in U.S. Pat. No. 3,505,680 comprises a pair of spaced lenses with an insulating air space therebetween.
The non-fogging goggles described in U.S. Pat. No. 3,591,864 also includes a pair of spaced apart lenses having a dead air space therebetween and a dehumidifier in the form of a tightly woven wire mesh portion made of a flexible metal of higher thermoconductivity.
A double-lens goggle is further recited in U.S. Pat. No. 1,562,350, wherein the inner sides of the interstice between the two lenses are covered with gelatin.
In Manufacturing Optician, Vol. 15, No. 6, March, 1962, p.275, a double-lens goggle is described, which also includes a small metal disc inserted into each side of the goggle frame. The metal disc acts as a condenser and draws the internally created moisture.
While the arrangements utilized in the aforementioned patents have a number of advantages, they have been found to be defective in the long run. Chemical treatment, such as lens coating, has turned out not to be permanent. Long-term exposure to moisture or large differences of temperature between the external atmosphere and the interstice of a double-lens goggle results in fogging. Forced air devices and electrically heated lenses are not practical for skier goggles and are also expensive.